1. Field of Invention
The invention relates to a method for monitoring an operating state of a device, a device for carrying out such a method, and a system for monitoring an operating state of a device.
2. Description of Related Art
In the operation of mechanical devices, there is a need to be able to detect the current operating state of a device. In connection with the present invention, the named operating states can be described by the current distance of two movable components from one another (for example, in the case of devices with components that are movable relative to one another). In the event of a vacuum handling device it is possible to distinguish different operating states (for example, with the help of pressure values of a vacuum supply). Likewise, an operating state can be characterized by the position of a piston or tappet in a cylinder. In the case of a gripping device, for example, it is possible to distinguish between an operating state with a gripped work piece and an operating state without a gripped work piece. The term “operating state” is therefore open to broad interpretation.
Different methods are known in the prior art for detecting operating states. These methods usually require an arrangement of sensors, wherein corresponding cabling is often used for signal transmission. Moreover, power supply from a power supply line or a separate battery is ordinarily required for a sensor. Further, known arrangements for detecting component position have switching features (for example, a dry reed contact switch or a pushbutton switch). However, these components are susceptible to wear and lead to a certain complexity of the detection system.
In published German patent application DE 10 2008 052 812 A1, a vacuum handling device is described wherein an RFID tag with an RFID chip and an antenna for wireless signal transmission is arranged on a component of this device. Between the antenna and the RFID chip, a switching element is provided, such that the antenna can be separated from the RFID chip and the RFID tag can be rendered functionless. The switching element is actuated by the contact of a work piece to be handled on the vacuum handling device, as a result of which the connection to the antenna is established. In this way, it is possible to monitor whether the component provided with the RFID tag is obstructed in the vacuum handling device.
Thus, there remains a need in the art for a simple, reliable, and energy efficient monitoring of operating states of a device. In particular, it is desirable to avoid expensive switch arrangements and conduit systems for power supply and/or data transmission.